Hypothermia in the management of traumatic brain injury. A systematic review and meta-analysis.

OBJECTIVE: Brain injury remains the leading cause of death in cases of trauma in North America and Europe. This article critically appraised and summarised all published and peer-reviewed, randomised, controlled trials of the use of hypothermia in traumatic brain injury.

DESIGN: To be included, a study had to be a published, randomised, controlled trial of the use of hypothermia in the management of traumatic brain injury. Pooling of data and meta-analysis of results occurred.

SETTING: Conducted at a tertiary level Canadian teaching hospital.

PATIENTS AND PARTICIPANTS: Patients were combined from eight randomised, controlled trials to generate a population of 748 severely head-injured patients.

MEASUREMENTS AND RESULTS: Eight studies provided data on the efficacy of hypothermia in the management of traumatic brain injury. The pooled odds ratio of mortality in the hypothermic group was 0.81 (95%CI =0.59-1.13, p=0.22). The OR of a poor neurological outcome (GOS 1,2 or 3) was 0.75 (95% CI=0.56-1.01, p=0.06). The odds ratio for pneumonia in the normothermic group was 0.42 (95%CI =0.25-0.70, p=0.001).

CONCLUSIONS: Although meta-analysis suggests that iatrogenic hypothermia may confer a marginal benefit in neurological outcome, there does not appear to be clear evidence of lower mortality rates in unselected traumatic brain injury patients. Prolonged hypothermia may confer a benefit, particularly in patients with elevated intracranial pressure refractory to conventional manipulations. Conclusions regarding the use of hypothermia are controversial and not strongly supported by the available evidence.